Recuperator construction



A. W. CATLlNv RECUPERATOR CONSTRUCTION 2 shets-sheet 1 INVENTOR. ARTHUR W. CA-rLm March 26, 1957 Filed Deo. 23, 195.4

March 26, 1957 A. w. cATLlN 2,786,666

RECUPERATOR CONSTRUCTION Filed Dec. 23, 1954 2 sheets-Sheet 2 INVENTOR. Aa-rHua W. CLA-n m gm/Tm A-f-rcnNtY iUnited States Patent() RECUPERATOR CONSTRUCTION Arthur W. Catlin, Manitowoc, Wis., assigner to- Manitowoc Shipbuilding Company, Manitowoc, Wis.

Application December 23, 1954,v SerialrNo. 477,170

2 Claims. (Cl 16S-$2) This invention relates toa recuperator construction'lfor a rotary kiln and is particularly directed to'allinerconstruction for the recuperator section of the'kiln.

In kilns such as cement kilns, it is the' -usual"prac'tice to preheat the combustion air by blowing the incoming air through the hot clinkers adjacent the discharge end of the kiln to thereby quench the clinkers and preheat the air. it frequently happens that small fragments of clinkers found their way Iinto vthe sub-frames forming the air ducts and, due to thevliner plate construction-previously used, were trapped in theseV ducts and plates and could not come out and, therefore, the ducts eventually became heavily loaded with particles. l v

in my prior Patent No. 2,477,287, of July 26, '1949, for Recuperator Construction, assigned to the same assignee as the present invention, l provided rectangularv openings in the trailing sides of the grates or liners, 4mainly "for the puipose of discharging clinker particles-which had gathered either in an interior pocket of the liner or'. else in the air ducts. While this construction was' a marked improvement over prior constructionsit nevertheless hatl the defect of discharging air through the `rectangular openings approximately tangentially ofthe recuperator. This produced a swirl in the iiame vand entraine'd coal dust, where pulverized coal was used, as well -as`-c'link'er dust, thus obscuring the visibilityin the kiln litself `and also producing a scouring actiony which wasf n'ot-de sirable, and further due to thesuspend'ed p'a-rticleslih the preheated air, causing abrasion and rapid wear of the primary air fan and other incidental'` equipment.

This invention is designed to overcome the above noted defects and objects of this invention are toprovide a yliner and recuperator construction in which-Itangential discharge of air is' eliminated v and instead" in which the air is discharged radially Vof Vthe kiln,i,n`wlii6h there is markedly vless accumulation of1 dust suspended in the cooling zone and in the preheated air, and in which there is a more uniformed depth of load on the liners, and in which the deep valleys between the liners are practically eliminated.

A further object of this invention is to provide a recuperator construction which provides for the elimination of clinker accumulation `in the air ducts and in which the small particles of clinkers and clinker dust in the air ducts is constantly eliminated by blowing such particles outwardly through small slots or openings in the discharge end of the recuperator by means of the air blast, such discharged clinker particles joining the main load ofthe kiln at the discharge end of the kiln if so desired.

Further objects are to provide a liner construction in which improved cooling of the clinker results by reason of the fact that the finer particles in the clinker bed pass through the radially arranged slots thereby increasing the voids in the load in the recuperator section of the kiln in a substantially uniform manner which results in increase of air capacity of the liners or grates due to the distributed voids and also due to the fact that the 2,786,666 Patented Mat. ,2.6, 19,57

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2i openings in the liners arranged in the' vrjaial manner provide in themselves an increased air capacity y all ',o'ff which produce favorable results and reduce theairpre'gsl sure requiredy for the recuperator unit.

Further objects are to provide better cooling'ojf the bolts which anchor the liners to the' outer shell thereby avoiding failure dueto burning off the boltheatis" in certain previousV con'structior'ns, were in close pro ity to lthe hot'clinker, this invention diifering fromrthepljior constructions lby providing a construction of liner which the bolt head is lowered into the air duct ad'is thereby effectively cooled by the' airblast'passi'ngthroligh the' ducts.

Ari-embodiment of the` invention is shown in 'the ac"- c'omp'ahying drawings in which:

Figure 1 is'a viewloo'king directly down on` ajliner.

Figure 2 isla sectional view on the line 2 2' of' ure l.

Figure 3 is a side view of the structure shown inFig# urev l witha part broken away anda part in section.

-Fig'ure4 is an endview of the liner.

Figure 5 isa longitudinal, fragmentary, sectional .View throughapoition of the recuperator section of the'kiln'i Figure 6 -is a sectional View on the line 6`-6` of Fig ureY 5.

Figure 7 is a sectional view drawn on a reduced scale through a portion of the recuperator section' of' the kiln showingthe clinker load and the manner in which the small-clinker particles fall into the air passages.

Referring to V4the drawings it will be seen from Figures 5,66 and 7, that the kiln is provided with an outer shell 10 ofrcylin'drical shape to which a plurality of liners inf' dicated' generally 'by the reference character 1'1 ar`e=bolted bymeans of the bolts 12, spacing sleeves 13 being'- post itioned between they transverse portion 14 of the liners and the outer'shellflfof the kiln. The ends of the linensjrefst upon longitudinallyextending narrow strips 15 which are'sec'ured tovsupporting webs 16 of therecuperator see# tion of the kiln asshownmo'st clearlyv in Figure 6. YIt'is to be noted that the webs 16 are not direetlys'ecured to the 'outer' shelllt) but are positioned between theinwardly extending arms of angle irons 17 which latter are se# cui-'ed tof the inner surface ofthe Ycylindrical shell 1 0- of the'kiln.

This construction is also utilized t'o p'rfovide th'e'aii passages 21S for the cooling air which passes into' the pass-ages successively as the kiln rotates and passes-out'- wardly through the slots inthe liners 11 as will here# inafter be described and inwardly through the clinker loadiindica'tedlat 19 in Figure 7. Thisair con'stitutesthe cooling-air and also after passing through the hotclinkers 19 is preheated and is used as preheated -air in theL kiln in a well-known manner.

The liner structures 11 are shown in considerable detail in Figures 1, 2, 3 and 4, to which attention is now directed. Each liner has an arched top 20 which is provided with a plurality of slots 2l extending axially of the kiln and also axially of the arched liner. These slots taper inwardly, or in other words are enlarged inwardly, so that any small clinker particles that pass into the slots will continue through the slots without any chance of wedging and thus without any chance of clogging the slots.

The liners are provided with axially extending cooling ribs 22, see Figure 2, which project inwardly and are thus positioned in the cooling air and assist in cooling the liners. In addition to this the liners are provided with opposed roughly triangular webs 23 which extend inwardly from the end walls 24 and project downwardly from the inner surface of the liners. The webs 23 are joined by the transverse portion 14 previously mentioned the bolt 12 resting upon the transverse member 1d.

, It will be seen from the construction thus far described that the bolt head 26 is positioned downwardly below the liner a considerable distance and is thus removed from the hottest portion of the liner. This construction greatly reduces the chance of the burning off of the heads of the bolts, for it will be seen that not only are the heads of the bolts positioned inwardly and spaced a considerable distance from the liners but also they are located directly in the cooling air stream. The bolts are provided with nuts 27 on the outer side of the cylindrical shell 10 of the kiln.

It is to be noted that the end walls 24 of the liners are apertured as indicated at 28 in Figure 4. This provides for the discharge of cooling air not only through the slots 21 of the liners but also from their end walls and into the space between successively axially positioned liners as shown in Figure 5. The liners are preferably provided with relatively narrow transversely extending, inwardly projecting webs 29.

Referring to Figure 7, it will be seen that ne clinker particles and clinker dust fall through the slots 21 into the air passages 1S and will collect in such air passages temporarily. The end wall 39 is provided with a plurality of openings of slots 3i on the trailing side of the air passages 1S. These openings or slots 21 are extended peripherally of the recuperator section of the rotary kiln and as stated are on the trailing side of the air passages 18. It will be seen therefore that as the kiln rotates in the direction indicated in Figure 7 that the clinker particles tend to collect at the trailing side of the air passages and are blown outwardly through the openings 31. They may be led back into the kiln in any suitable manner, not shown, or may be completely discharged from the kiln.

It has been found that the kiln is very much more eicient and requires a lower air pressure than heretofore required due to the fact that voids are formed in the clinker load due to the falling out of the small clinker particles. These voids allow freer passage of air through the clinker load and thus the required air pressure is less. In addition to this all of the slots leading through the top wall of the liners are radially arranged and consequently there is no tendency to produce a whirling action in the recuperator section of the kiln. Further than this the liners are of relatively light weight and not as bulky as the previously known types of liners.

Other advantages result from the 'use of the liners i avancee While this invention has been described as applicable to'a'cement kiln, it is understood that the construction is equally applicable to lime kilns or kilns for other refractory materials.

Although this invention has been described in considerable detail, it is to be understood that such description is intended as illustrative rather than limiting as the invention may be variously `embodied and is to be interpreted as claimed.

l. A recuperator construction for a rotary kiln comprising a series of rings of arched, hollow liner members having roofs arched about an axis substantially paralleling the axis of the kiln and having a series of air discharge openings, an outer cylindrical shell, a series ot" webs extending longitudinally of said kiln and located between said liners and said shell and dening air supply passages, and an annular end wall closing the outer ends of said air passages, said annular end wall having openings therein for the discharge of small. clinkers which have passed through the air discharge openings in said liner members, said last mentioned openings being relatively small as compared with the cross sectional area osaid air passages, the openings in said end wall being located adjacent said shell and adjacent a corner of the several air passages, said kiln being designed to rotate in-a direction such that the said corners are the trailing corners.

2. A recuperator construction for a rotary kiln cornprising a series of rings of arched, hollow liner members having roofs arched about an axis substantially paralleling the axis of the kiln and having a series of air discharge openings, an outer cylindrical shell, a series of webs extending longitudinally of said kiln and located between said liners and said shell and defining air supply passages, and an annular end wall closing the outer ends ot said air passages, said annular end wall having openings therein for the discharge of small clinkers which have passed through the air discharge openings in said liner members, said last mentioned openings being relatively small as compared with the cross sectional area of said air passages, the openings in said end wall being located adjacent said shell and adjacent a corner of tbe several air passages, said kiln being designed to rotate in a direction such that the said corners are the trailing corners, and said ropenings being elongated peripherally of said shell.

l References Cited in the le otthis patent UNITED STATES PATENTS 1,902,517 Newhouse Mar. 2l, 1933 2,266,396 Lincoln et al. Dec. 16, 1941 2,276,589 Peltier et al Mar. l7, 1942 2,477,287 Catlin July 25, 1949 

